As talks at the Labour Relations Commission between Aer Lingus management and pilots' representatives aimed at averting a threatened dispute continued last night with no sign of a breakthrough, pilots in the US have offered $1 million (€714,000) to support their Irish colleagues.
Up to 15,000 passengers daily could be affected if Aer Lingus flights are grounded as a result of the dispute.
Sources close to the trade union Impact, which represents pilots, said there was less optimism last night than earlier that the talks would succeed.
Meanwhile, separate talks at the LRC last night averted a rail strike that would have badly affected services between Dublin and the southwest.
All Iarnród Éireann services to and from Cork, Kerry and Limerick will this morning operate normally after management and the union negotiators from Siptu and the National Bus and Rail Union agreed a document that will come up for discussion at the Labour Court next week.
In a separate development, The Irish Timeshas learnt that the Allied Pilots' Association, which represents staff at American Airlines, has offered up to $1 million in financial support to Irish pilots in the event of what unions have described as a lock-out by Aer Lingus management taking place.
A spokesman for the association said the money would come in the form of donations from its 9,000 pilots as well as loans.
Aer Lingus said yesterday it was still operating on the basis that it would be providing a full service this week.
The airline has said it will suspend pilots if they refuse to co-operate with moves to facilitate the opening of its planned new base in Belfast. It has said that unless the undertakings are received by lunch-time today, the pilots will be removed from the payroll from tomorrow morning.
Talks between management at Aer Lingus and pilots' representatives at the LRC over the weekend lasted more than 15 hours.
However, there were no indications of a breakthrough.
It is understood the parties spent much of the weekend dealing with issues such as pensions and the impact of the new Belfast base on the seniority and promotional rights of existing pilots.
Aer Lingus has said the dispute is about the future of the company and who is running and driving the business. It has accused the pilots of seeking an effective veto over the company in terms of the development of new bases outside the Republic of Ireland.
The Irish Airline Pilots' Association (Ialpa), which is a branch of the trade union Impact, has said it accepts that the cost base for pilots would be lower in Belfast. However, it wants a role in negotiating the terms and conditions to apply in Belfast.
Ialpa also has concerns about the pension scheme and the rights of pilots to transfer between the airline's various bases. It has placed a ban on members co-operating with the opening of the base in Belfast.
Already seven pilots have been suspended without pay in the course of the current dispute.
Speaking on his way in to the talks yesterday, Michael Landers, the assistant general secretary of Impact, said pilots had come to do business. He said the pilots were willing to remain in negotiations for as long as necessary.
Aer Lingus chief executive Dermot Mannion said the company would give the talks its best shot. Aer Lingus has said that despite the talks over the weekend, its deadline of lunch-time today for agreement from pilots to co-operate in the recruitment and training of candidates for the new base remained.
Ialpa president Evan Cullen said its policy of non co-operation also remained.
LRC chief executive Kieran Mulvey said management and the union had been positive in their attitudes during talks on Saturday.